As a visual-field test apparatus for testing a visual field of a human, for example, Humphrey visual field analyzer is known. This visual field analyzer presents a visual target at one of a plurality of predetermined points located on a spherical visual field dome. A subject holds fixation on a fixation visual target located at a predetermined position, and when the subject can see the presented visual target, the subject presses a response switch. The visual target is, for example, a light spot projected at a point on the visual field dome. While the luminance and the presentation position of the light spot are changed, whether or not the subject presses the response switch is examined. Thereby, the visual field, and the visual sensitivity (referred to as a threshold) at a specific position of the visual field of the subject can be tested.
According to a conventional visual-field test apparatus, the position where a visual target is to be presented is determined by, for example, presenting a visual target at a predetermined position, examining whether the visual target presented at the position is visible or not, and thereafter, presenting a visual target at a visual target presentation position which is adjacent to the predetermined position and is closer to the fixation visual target, and so on. That is, visual targets are sequentially presented while the presentation positions are changed from the outer side of the visual field toward the fixation visual target.
According to a strategy for a threshold test, a luminance at a visual target presentation position is reduced in stages from a visible luminance to an invisible luminance, by a drop of 4 dB each time, and then, is raised in stages from the invisible luminance, by an increase of 2 dB each time, to thereby find a threshold. The same process is repeated at another visual target presentation position for the next threshold test.
Further, Japanese Unexamined Patent Publication (Kokai) No. 2005-102947 discloses a visual-field test apparatus for obtaining an evaluation value on the basis of responses of a subject, using a probability function, in order to obtain an objective evaluation value.